Kirk apparently can't tell his left from his right. He points right and tells Spock to go left, then he points left and say's he'll go right. Apparently, Spock can't tell either because he heads off in the direction Kirk pointed in rather than the way he was told to go.

Great Moment :

McCoy's amazement when he cures the Horta. He's almost spookily pleased with himself!

Body Count :

Two people killed by the Horta.

Factoid :

A Horta appeared in several of the novels as an Enterprise crewmember!

This is the only original series episode in which the ship and crew are absent from the teaser.

William Shatner's father died during the filming of this episode. Although he was told that they would shut down production so that he could fly home, he insisted on remaining to complete the day's work before catching a flight.

Janos Prohaska created the Horta design. He wore it and shuffled into producer Gene L. Coon's office to surprise him, laying a silicon "egg" in the middle of the floor and shuffling off again. Coon was so impressed with the performance that he wrote the episode specifically to showcase it.

Gene Roddenberry would praise this episode as a great example of a monster that, once understood, suddenly became a person that the audience could identify and sympathise with.

In one of his books Shatner has claimed that this was his favourite episode.

No less than Arthur C. Clarke has also cited this as the best episode of the original series as "it presented the idea, unusual in science fiction then and now, that something weird, and even dangerous, need not be malevolent."

Plotline

On Janus VI, the Federation runs a mining colony to exploit the fabulous range of mineral resources on the planet. However, operations are being disrupted by the mysterious deaths of many of the miners. The Enterprise arrives to investigate and resolve the problem. The head of the colony, Vanderberg, informs Kirk that they believe there is some sort of terrible creature in the mines, something that has killed more than fifty people and sabotaged machinery. As a result pergeum production has been completely halted, a serious matter since the material is vital to the Federation. Descriptions of the creature are very vague, with only one man having seen it and survived. The man reported shooting the creature with his phaser, but the weapon had no effect. Vanderberg is skeptical of Kirk's ability to help, given how powerless the Enterprise is against something that lives in tunnels miles beneath the surface.

Spock notices a geological oddity in Vanderberg's office, a perfectly round silicon nodule. Vanderberg tells him there are huge numbers of them down in the tunnels, a worthless curiosity. McCoy analyses the remains of a dead miner and finds that it has been corroded away almost to nothing by some sort of extremely powerful acid. As they talk about the findings, an alarm sounds; the creature has attacked again, killing a guard and removing the main circulating pump of the colony reactor. Without it the reactor cannot be controlled, and will go critical and irradiate half the planet within hours.

Fortunately Scotty is able to improvise a repair, but without the proper equipment it is a stopgap at best, and will last no more than 48 hours. They have that long to find the original unit.

Spock suggests that they may be dealing with some sort of silicon-based creature. Such a being might not show on their sensors, which are designed to detect carbon-based life. It might also be resistant to phaser fire since it would effectively be a living rock. Kirk brings down security teams from the Enterprise, with their phasers - more powerful than the ones the miners have been using - modified to be effective against silicon. Kirk orders the creature attacked on sight with maximum phaser fire.

One of Kirk's men is quickly killed by the creature. Kirk and Spock manage to get a shot off at it, injuring it as it escaped. A fragment of the creature proves that Spock is correct about it being silicon based. Scans indicate that only one such creature is within a hundred mile radius. Spock states that this implies the creature is one of a kind, and killing it would thus eradicate the species - something he is very reluctant to do. Kirk, however, is determined to destroy it anyway. When Spock suggests to the security teams that they attempt to capture the creature Kirk overrides him with a shoot to kill order, and then suggests that Spock might be better suited to assisting Scotty rather than hunting in the tunnels. Spock, however, manages to convince Kirk that he should remain.

The improvised pump fails, producing near panic amongst the miners. Although the Enterprise guards manage to hold them back, they are determined to track the creature down and attack it. Meanwhile in the tunnels Kirk finds a chamber filled with hundreds of the silicon nodules. Spock warns Kirk that it is important that he does not damage any of them, though he declines to explain why. Suddenly Kirk is sealed in by a rock fall, and finds himself facing the creature.

When Kirk raises his phaser the creature backs off and he holds off from firing, even though Spock now urges him to kill it to protect himself. Kirk senses an intelligence to the creature, noting that it is wounded. Spock makes his way to Kirk's location and they talk about what to do. Spock agrees to do a mind meld and learns the full story; the creature is a Horta, a member of an intelligent species native to the planet. It is in absolute agony as a result of the wound, and Kirk brings McCoy down to treat it. The Doctor is hesitant, as he knows absolutely nothing about the Horta, but he quickly improvises a solution - he patches the wound with quick setting concrete, which acts as a bandage. They are able to recover the pump from a nearby chamber. The treatment apparently helps the Horta, and Spock melds with it again. The full story emerges; every fifty thousand years os so the Horta die off, with the exception of a single individual who has the role of guarding the millions of eggs that they leave behind - the silicon nodules which the miners have been carelessly destroying.

The miners overpower the guards and make their way down to the chamber, determined to kill the Horta - but the group is brought short when Kirk points out that whilst she has killed over fifty of them, she was only acting in defence of her species after they killed thousands of her children. Kirk points out that millions of Horta are about to hatch, and that the very first thing a baby Horta does is begin to tunnel - soon half the planet will be criss-crossed with tunnels, which the miners will be able to use to get at massive new mineral deposits. If they learn to live and work with the Horta, they will soon be embarrassingly rich! The thought sways the miners, and with the pump reinstalled the officers return to the ship. Vanderberg subsequently calls to tell them that the Horta have hatched and already found new mineral deposits. He comments that they don't even look too bad once you get used to them, and Spock comments that the Horta had said much the same thing about them - and that she had a particular soft spot for his Vulcan ears.

Analysis

What's not to like about this one? The setup is good - we're so used to seeing the ship out amongst the stars, or the crew on the surface of a planet, that to find them suddenly having to be down in the tunnels, alone in the dark as the monster prowls, gives the show a genuinely eerie and slightly frightening edge. As a monster, the Horta is a good one - able to tunnel through solid rock at will, fast, utterly inhuman, virtually impervious to anything you can throw at it, and above all deadly. With fifty men dead, you know that it is a fearsome opponent and a credible threat to our heroes.

There's a nice little twist generated between Kirk and Spock, too, with the first officer hesitant to kill the creature and Kirk bullishly determined to do just that. The attitude fits both of their characters perfectly. And yet we should note that this is actually an example that Kirk is not the stereotype that is often attributed to him. The idea has arisen over the years that Starfleet officers of this period, and Kirk in particular, were rather "quick on the draw", practically eager to resort to force to resolve their problems. Well Kirk does want to kill the Horta, but he has ample reason to do so given that the thing has left a trail of over fifty dead bodies behind it! And yet, when he actually has the creature in his sights, what does he do? With even Spock telling him urgently to shoot it lest he lose his own life he instead holds his fire, based on nothing but the feeling that there is intelligence to the creature. And as soon as he comes to find that there is a non-violent way out of this situation, Kirk unhesitatingly takes it and forces everybody else to take it too. No, Kirk is most emphatically not the "we come in peace - shoot to kill!" stereotype that he is so often made out to be. Far from it, in fact.

Of course, the real genius of the episode is the twist that the Horta is simply protecting her eggs. In that one moment the entire plot flips from being about an evil monster to being about a mother who is simply defending her children the only way she knows how. We go from being scared of her to being on her side, in an instant. It's a truly inspired moment.